Fully integrated RC oscillators are limited in performance compared to oscillators that use a high Q resonator such as crystal oscillators. Initial frequency accuracy, frequency drift over temperature and voltage and phase noise are always worse in fully integrated oscillators than in an oscillator including a high Q resonator. However, it is desirable to use RC oscillators instead of crystal oscillators. Such RC oscillators can be fully integrated in a CMOS technology, thereby reducing complexity and production costs.